<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>cookie示例</title>
</head>
<body>
    <script>
        // 界面打开调用cookie判断函数
        window.onload = function () {
            checkCookie();
        };

        // 保存cookie
        function setCookie(cname, cvalue, exdays) {
            var d = new Date();
            // console.log(d);
            d.setTime(d.getTime() + exdays * 24 * 60 * 60 * 1000);
            var expires = 'expires=' + d.toGMTString();
            // console.log(expires)
            document.cookie = cname + '=' + cvalue + ';' + expires;

        }
        
        // 获取cookie
        function getCookie(cname) {
            var name = cname + '=';
            var ca = document.cookie.split(';');
            for (var i = 0; i < ca.length; i++) {
                if (ca[i].indexOf(name) >= 0) {
                    return ca[i].split('=')[1];
                }
            }
            // return '';
        }

        // cookie判断函数
        function checkCookie() {
            var user = getCookie("username");
            if (user) {
                alert("欢迎【" + user + "】再次访问！");
            } else {
                user = prompt("请输入你的名字：", "");
                if (user) {
                    setCookie("username", user, 5);
                }
            }
        }
    </script>
</body>
</html>